Next-generation communication systems have evolved to provide a variety of high-speed, high-capacity services to User Equipments (UEs). Long Term Evolution (LTE) communication system, an example of the next-generation communication systems, uses various resource allocation schemes, one of which is blind scheduling.
The blind scheduling is a scheme in which an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) Node B (eNB) periodically allocates a dedicated uplink (UL) resource without prior information about the amount of data that a UE will transmit over an UL. The LTE communication system considers using blind scheduling for latency reduction. The amount of data that a UE will transmit over a UL may be detected using the buffer status. For convenience, a dedicated UL resource that is periodically allocated to a UE using blind scheduling will be referred to herein as a ‘UL grant’.
When employing blind scheduling, an eNB continuously allocates a dedicated UL resource or a UL grant to a UE for a relatively long period. So, the UE is continuously allocated the UL grant by the eNB such that, even when the UE has no data, it will actually transmit on a UL.
Semi-Persistent Scheduling (SPS) is one of the blind scheduling schemes. When using SPS, an eNB periodically allocates a UL grant to a UE to which an SPS Cell Radio Network Temporary Identifier (C-RNTI) has been allocated. The eNB may inform the UE of a UL grant allocation period using an SPS configuration Information Element (IE). The UE may transmit data to the eNB using the periodically allocated UL grant. Therefore, the UE may skip the UL resource allocation process that it should perform with the eNB to be allocated a UL resource, contributing to a reduction in the latency.
When the LTE communication system uses SPS, the latency may be reduced due to the possible skip of the UL resource allocation process. However, a UE should transmit padding Medium Access Control (MAC) Protocol Data Units (PDUs) using a UL grant even when it has no data to transmit on a UL, which may cause a waste of the UE battery and lead to signaling overhead caused by the transmission of the padding MAC PDUs. In addition, the eNB unnecessarily decodes the padding MAC PDUs, causing a padding MAC PDU decoding processing load.